It is known that Ethernet has become the most ubiquitous networking technology in Local Area Network (LAN) environments. Given its popularity in the enterprise domain, there is a growing effort to replicate its success in telecommunications service provider networks. This has led to proposals to create next-generation Ethernet-based services across metropolitan and national Wide Area Networks (WANs).
To standardize these services, the telecommunications industry has classified them under two broad categories: (1) Ethernet Line (E-Line) services for point-to-point connectivity; and (2) Ethernet LAN (E-LAN) services for multipoint-to-multipoint (any-to-any) network connectivity. E-LANs have applications in multipoint Ethernet Virtual Private Networks (VPNs) and Transparent LAN services and is particularly advantageous because, unlike Frame Relay, E-LAN promises to provide multipoint-to-multipoint connectivity.
In order to deliver these services, some service providers have taken the approach of supporting Ethernet on their legacy Synchronous Optical Network (SONET) or Synchronous Digital Hierarchy (SDH) transport infrastructures (for simplicity herein, the word SONET will be used to refer to both SONET and SDH). Their approach aims to encapsulate Ethernet at the edge and transport it over the SONET infrastructure. Such an approach is referred to as Ethernet-over-SONET (EoS).
It is also known that a spanning tree is very important to any Ethernet network. Protocols such as IEEE (Rapid) Spanning Tree Protocol (IEEE 802.1d, 802.1w), the disclosure of which is incorporated by reference herein, are used by Ethernet nodes to select a spanning tree of the network along which to forward data frames. However, while Asynchronous Transfer Mode (ATM) and Frame Relay-based data networks deploy data services that are considered “carrier class,” i.e., their services support service-level agreements (SLAs) that guarantee various performance metrics such as bandwidth and downtime, traditional enterprise Ethernet and associated spanning tree computations are merely “best effort” in nature with respect to performance considerations.